Off-shore ship mooring installation

ABSTRACT

AN OFF-SHORE SHIP MOORING INSTALLATION MADE UP OF A WHARF IN THE FORM OF A COLUMNAR BODY BUILT ON THE BOTTOM OF THE SEA AND HAVING A CIRCULAR MOORING HEAD THAT PROJECTS ABOVE THE SEA IN COMBINATION WITH A STRING OF DOLPHINS DISTRIBUTED ON A CIRCLE CIRCUMSCRIBING THE MOORING HEAD AND LOCATED AWAY FROM THE SAID HEAD A DISTANCE   SUCH AS TO ALLOW MOORING OF THE STEM OF ONE OR MORE SHIP WHEN THE THE SHIPS ARE MOORED TO THE HEAD BY THE BOW THEREOF.

Feb. 16,1971 B. MICHEL OFF-SHORE SHIP MOORING INSTALLATION 2 Sheets-Sheet 1 Filed March 14, 1969 //v WEN/'01? Bernard M/Cf/[L ATTORNEY Feb. 16, 1971 B. MICHEL 3,563,041

OFF-SHORE SHIP MOORING INSTALLATION I Filed March 14, 1969 ,2 Sheets-Sheet? IN VENT 0/? Bernard M/ CY/E L ATTORNEY United States Patent 3,563,041 OFF-SHORE SHIP MOORIN G INSTALLATION Bernard Michel, 739 Rue des Vignes, Ste.-Foy, Quebec 10, Canada Filed Mar. 14, 1969, Ser. No. 807,236 Int. Cl. E02b 3/22; E02d 27/36 US. Cl. 61-46 5 Claims ABSTRACT OF THE DISCLOSURE An off-shore ship mooring installation made up of a wharf in the form of a columnar body built on the bottom of the sea and having a circular mooring head that projects above the sea in combination with a string of dolphins distributed on a circle circumscribing the mooring head and located away from the said head a distance such as to allow mooring of the stern of one or more ships 'When the ships are moored to the head by the bow thereof.

The present invention relates to a ship mooring installation and more specifically to an off-shore installation.

With the increase in the exploitation of mineral resources far at sea, particularly the tapping of oil reserves in arctic seas, there is a need for an appropriate mooring installation. Furthermore, apart from providing simple mooring of a ship, far at sea, such installations are also expected to afford the usual services rendered by a harbor such as shelter against ice movement and storms, whatever be their direction; loading up of ships, usually tankers, with oil either directly from a pipe line or from a reservoir; refuelling and repairing of the ships; providing sundry supplies, etc. Now, several solutions have been proposed in the form of wharves of various shapes but all fail to properly solve the problem of ice accumulation in front of, and eventually, all around the wharf, thus quickly rendering the wharf totally useless at least during the nine months of the year that the winter lasts in the regions Where such wharves are to be provided.

It is indeed a prime requirement that such wharves be made available all year round, that is, that ice accumulation not prevent the berthing of ships at any time. Present tankers of considerable size up to 100,000 tons are now in use and tankers having capacity of 250,000 tons are being contemplated but although such tankers are built as ice breakers, the severe ice conditions in arctic seas must be clearly visualized before the solution brought by the present invention can be fully appreciated. It must be realized that, in arctic seas, large fields of ice having an area of several square miles are constantly in movement nine months of the year, their velocity and direction of displacement depending on the velocity and direction of the prevailing currents and winds. Any obstacle in the path of such fields causes rapid accumulation of ice all around it that eventually builds up, with the obstacle becoming an inaccessible island of ice. Wharf constructions that have so far been proposed are so designed that they precisely would cause such accumulation.

Another aspect of such installations is that it must provide proper shelter during heavy storms, not only to prevent damage to the ships, but also to allow normal loading activities even during storms.

It is consequently a main object of the invention to provide a ship berthing elf-shore installation that will not be prone to the accumulation of ice and that will afiFord shelter against movement of ice fields as well as storms, whatever be their direction.

Another object of the invention lies in the provision 3,563,041 Patented Feb. 16, 1971 of an offshore ship mooring installation that will provide a shelter area whereby ships will be able to carry on normal loading activities even during storms.

More specifically, the invention lies in the provision of an off-shore ship mooring installation that comprises a wharf formed by a columnar body built on the bottom of the sea and having a circular mooring head projecting above the sea whereby the body creates a lee area. The installation further comprises first mooring means at the bottom of the sea located away from the circular head a distance such as to allow mooring of the stern of a ship in the lee area when the ship is moored to the head by the bow thereof, and second mooring means peripherally distributed on the mooring head to allow securing of the bow of a ship in the lee area. In this manner, the mooring installation allows berthing of ships in a sheltered area with their longitudinal axis extending radially of the mooring head.

A better understanding of the invention will be afforded by the description that follows having reference to the appended drawings wherein:

FIG. 1 is a plan view of a mooring installation according to the invention as seen surrounded by stormy waves;

FIG. 2 is a plan view of the installation, similar to that of FIG. 1, but showing the installation are surrounded by a field of ice;

FIG. 3 is a transverse cross-sectional view, in elevation, of the installation of FIGS. 1 and 2.

Referring now to the drawings, it will be seen that the installation comprises a wharf 1 formed as a columnar body, that is, a structure accessible all around. Wharf or body 1, made of concrete, is formed of a pillar base 3 topped by a frusto-conical capital 5 over which a circular mooring head 7 is built. As illustrated, the pillar base 3 is completely submerged while the frusto-conical capital 5 lies partly in and partly out of water with the disclike mooring head 7 completely out of water. In this manner, the inclined outer surface of the capital 5 will serve to break any ice that may come against it and will prevent accumulation. Pillar base 3 may be formed by prefabricated caissons, in the form of an annular ring, sunk in the bottom of the sea, the capital 5 and mooring head 7 being constructed thereover. The latter mooring head 7 may be hollowed out and formed with a floor 9 and a ceiling or roof 11. The inner space, thus formed, may be partitioned to provide storing and housing areas. The space beneath floor 9 and confined by the outer walls of the capital 5 and the base 3 may be filled with earth, it being understood that the lower level of the earth fill will gradually become water soaked. If the mooring installation serves for tankers in the case of an oil exploitation, an oil reservoir 15 may be provided. Of course, oil may also be derived directly from a pipe line installation.

As to the partitioning of space 13 as well as constructional details of Wharf 1, it will be appreciated that these are well within the realm of present engineering knowledge and need not be described any further.

With reference to FIGS. 1 and 2, it will be understood that such a structure as aforedescribed will provide a lee or sheltered area 18, delimited in FIGS. 1 and 2 by broken lines. Because of this particular structure, the surface of the sea in the lee area 18 of FIG. 1, Will be relatively calm as compared to the surface outside area 118 where the waves, created by winds, are coming from the direction indicated by arrows A.

Similarly, FIG. 2 illustrates an ice field 20 being driven by currents or winds in the direction indicated by arrow B. Again, a lee area 118' will be defined by the protected side of the wharf .1. Because of the absolute absence of angularity in the structure of the wharf, there will be no accumulation of ice on the side thereof opposite the lee area 18, the field of ice smoothly flowing around the curved structure.

In combination with the circular wharf 1 above described, the invention comprises first mooring means at the bottom of the sea located away from the circular head 7 a distance such as to allow mooring of the stem 17 of the ship, such as a tanker 19, in the lee area 18 when ship 19 is moored to head 7 by the bow thereof. Preferably, the first mooring means is a string of dolphins, illustrated in FIGS. 1 and 2 by dots 21, distributed on a circle 23 circumscribing the mooring head 7. Dolphins 21 may be of the conventional type, such as cleats, the mooring cables, fixed at one end to the stern 17 and carried by a servicing tug, being dropped to the bottom of the sea and wound around the said cleats 21 for securement. Obviously, other types of dolphins may be considered and the fastening of such dolphins at the bottom of the sea being also conventional,

Thus, the combination according to the invention which is made up of wharf (1 having a mooring head 7 and the string of dolphins 21 allow a ship such as tanker 19 to berth in the lee area 18 with the longitudinal axis thereof extending radially of the mooring head 7. By properly selecting the diameter of wharf 1 in relation to the length of ship 19 and the characteristics of ice and waves, it is possible to ensure that the latter will stand completely in the sheltered area 18. As an example, I have estimated that a 100,000 ton tanker having a length of 1,000 feet would require a mooring head 7 having approximately 1,250 feet in diameter while the pillar base 3 would have an outer diameter of approximately 1,150 feet.

The bow 27 of the ship will be tied to the mooring head 7 by conventional mooring means such as known cleats 29, 29' and mooring cables 31.

As will be realized, the lee area 18 may lie anywhere around wharf t1 and, consequently, cleats 29 would have to be provided all around the periphery of the mooring head 7. This may be done by having cleats 29' right on the periphery of floor 11 (FIG. 3) or in recesses around the vertical wall of the mooring head 7, or both.

Ships, such as oil tankers 19, intended to moor against wharf 1 are preferably provided with a specially designed deck 33 provided at the bow 27 of the ship. It will be noted that deck 33 has an arcuate front edge 35 adapted to abut the mooring head 7. Edge 35 may be provided with a conventional fender to avoid damage to deck 33. The curvature of edge 35 may preferably correspond to that of a circle whose center is that of the center of gravity of the ship.

In FIG. 2, there is shown blocks of ice 37 that were detached from the field of ice 20 or were formed within the lee area 18. However, such ice blocks 37 would not cause any difficulty and any tendency of them to accumulate around the ship may easily be broken up and cleared by the servicing tug that constantly stands by and is part of the harbor servicing equipment.

In view of the size of the mooring head 7, the roof 11 thereof may serve as a landing platform for a helicopter and if a wharf of larger size is built, such as for use with 250,000 ton tankers, the size of the roof 11 would be such as to aiford landing by an aircraft. Obviously, tank 4 would have to be removed for such purpose or made to lie wholly within wharf 1.

Although the preferred embodiment just described is in relation to use of the invention in arctic seas, it will be appreciated that the mooring installation of the invention can also be used in moderate or tropical climatic areas. Also, such otf-shore installations are obviously intended to be built on the continental shelf where the depth of water is within practical limits.

I claim:

1. An ofi-shore mooring installation comprising:

(a) a wharf formed by a columnar body built on the bottom of the sea and having a circular mooring head projecting above the sea, said body having a diameter large enough so as to deflect ice and reduce wave amplitude and to create a lee area of sufficient size to allow berthing of a ship completely whatever be the direction of ice and waves;

(b) a plurality of first mooring means at the bottom of the sea; said mooring means located away from and around said circular head a distance such as to allow mooring of the stern of said ship in said area when said ship is moored to said head by the bow thereof, and

(c) a plurality of second mooring means peripherally distributed on said mooring head to allow securing of the bow of said ship in said lee area whereby said mooring installation allows berthing of a ship in said lee area in any position around said head and with the longitudinal axis thereof extending radially of said mooring head.

2. An installation as claimed in claim 1 wherein said first mooring means is a string of dolphins distributed on a circle circumscribing said mooring head.

3. An installation as claimed in claim 2 wherein each dolphin is of the cleat type, the mooring cables being dropped to the bottom of the sea and wound around said cleats for securement.

4. An installation as claimed in claim -1, in combination with ships having an arcuate deck of substantial width at the bow thereof adapted to abut said mooring head, said deck having a radius whose center is the center of gravity of said ships, and mooring cables tying both lateral ends of said arcuate deck to said head.

5. An installation as claimed in claim 2, in combination with ships having an arcuate deck of substantial width at the bow thereof adapted to abut said mooring head, said deck having a radius whose center is the center of gravity of said ships, and mooring cables tying both lateral ends of said arcuate deck to said head.

References Cited UNITED STATES PATENTS 3,093,167 6/1963 McCammon 6146X 3,209,545 10/1965 Cook 61-48 3,354,479 11/1967 Koppenol et al. 114-230X J. KARL BELL, Primary Examiner U.S. Cl. X.R. 61-48; 114230 

